Method for taking out a sealing plate of a fuel cell and a sealing plate directly used in the method

ABSTRACT

A fuel cell sealing plate taking-out method that may include taking out a sealing plate from a stack of sealing plates one by one while an air layer exists between adjacent sealing plates of the stack of fuel cells. A protrusion may be formed beforehand at one or more surfaces of each sealing plate. Due to the air layer existing between adjacent sealing plates, it may be possible to take out the sealing plate one by one from the stack of sealing plates.

This is a continuation of application Ser. No. 12/296,289 filed 7 Oct.2008, which is a 371 national phase application of PCT/JP2007/055646filed 20 Mar. 2007, which claims priority of Japanese Patent ApplicationNo. 2006-108735 filed 11 Apr. 2006, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a fuel cell sealing plate taking-outmethod for taking out a fuel cell sealing plate one by one from a stackof fuel cell sealing plates and a sealing plate directly used in themethod.

BACKGROUND

A fuel cell is constructed from an MEA (Membrane-Electrode Assembly) andseparators sandwiching the MEA. A gas diffusion layer is disposedbetween the MEA and the separator. In the separator, at a powergenerating region, a fuel gas passage or an oxidant gas passage isformed at a surface of the separator facing the MEA, and a coolantpassage is formed at a surface opposite the surface facing the MEA.Further, in the separator, at a non-power generating region located atan outer portion of the separator, a fuel gas manifold, an oxidant gasmanifold and a coolant manifold are formed. The fuel gas passagecommunicates with the fuel gas manifold via a fuel gas inlet/outletpassage, and the oxidant gas passage communicates with the oxidant gasmanifold via an oxidant gas inlet/outlet passage. The gas inlet/outletpassage includes a gas passage groove formed at a bottom surface of thegas inlet/outlet passage and a sealing plate disposed at the gasinlet/outlet passage and covers the gas passage groove.

As disclosed in Japanese Patent Publication 2001-110436, the sealingplate is constructed of a stepped plate in order to prevent interferencewith the diffusion layer.

BRIEF SUMMARY

Certain embodiments of the present invention relate to cases where afuel cell or fuel cell module is automatically assembled and it may benecessary to take out a sealing plate one by one from a stack of sealingplates supplied and to supply the taken-out sealing plate to a gasinlet/outlet passage of the fuel cell.

Since the sealing plate is constructed of a flat plate, when the sealingplates are stacked, the sealing plates are likely to adhere to eachother, because the sealing plates closely contact each other due to alow pressure and/or due to a static electricity at the contact portion.As a result, it may be difficult to separate the sealing plates one byone from each other.

An object of certain embodiments of the present invention is to providea fuel cell sealing plate taking-out method for taking out a fuel cellsealing plate one by one from a stack of fuel cell sealing plates, and afuel cell sealing plate directly used in the method

Certain embodiments of the present invention may include the followingmethods and sealing plates:

(1) A method for taking out a sealing plate of a fuel cell one by onefrom a stack of sealing plates, the sealing plate to be installed to agas inlet/outlet passage of a fuel cell so as to cover a gas passagegroove formed at the gas inlet-outlet passage, the method comprising:

a first step of taking out the sealing plate one by one from the stackof sealing plates under a state that an air layer exists betweenadjacent sealing plates; and

a second step, provided between the first step and a step of installingthe taken-out sealing plate to the fuel cell, of (a) placing thetaken-out sealing plate on a suction plate and sucking the sealing platefrom opposite sides of the sealing plate by the suction plate and asuction pad, and (b) stopping conveyance of the sealing plate to thestep of installing the taken-out sealing plate to the fuel cell whentaking-out of two sealing plates is detected,

wherein in order to obtain the state that an air layer exists betweenadjacent sealing plates of the stack of sealing plates at the firststep, a protrusion is beforehand formed at an at least one surface ofeach sealing plate and at a portion of the sealing plate whichcorresponds to a portion of a sealing plate installing place of the fuelcell in a direction perpendicular to a gas flow direction at the sealingplate installing place.

(2) A method according to item (1) above, wherein the sealing plate ismade from synthetic resin.

(3) A sealing plate of a fuel cell directly used for a method of takingout a sealing plate from a stack of sealing plates, the sealing plate tobe installed to a gas inlet-outlet passage of a fuel cell so as to covera gas passage groove formed at the gas inlet-outlet passage, the methodincluding:a first step of taking out the sealing plate one by one from the stackof sealing plates under a state that an air layer exists betweenadjacent sealing plates of the stack of sealing plates; anda second step, provided between the first step and a step of installingthe taken-out sealing plate to the fuel cell, of (a) placing thetaken-out sealing plate on a suction plate and sucking the sealing platefrom opposite sides of the sealing plate by the suction plate and asuction pad, and (b) stopping conveyance of the sealing plate to thestep of installing the taken-out sealing plate to the fuel cell whentaking-out of two sealing plates is detected,the sealing plate comprising:a protrusion is beforehand formed at an at least one surface of eachsealing plate and at a portion of the sealing plate which corresponds toa portion of a sealing plate installing place of the fuel cell in adirection perpendicular to a gas flow direction at the sealing plateinstalling place.(4) A sealing plate of a fuel cell according to item (3) above, whereina position, a width and a height of the protrusion of the sealing plateare determined such that the protrusion of the sealing plate is housedin a gas passage groove of a gas inlet/outlet passage of the separatorwhen the sealing plate is installed to the fuel cell.(5) A sealing plate of a fuel cell according to item (4) above, whereinthe width of the protrusion of the sealing plate is equal to or smallerthan a width of the gas passage groove.(6) A sealing plate of a fuel cell according to item (3) above, whereinthe protrusion is formed at a surface of the sealing plate opposite to asurface of the sealing plate facing a bottom surface of the gas passagegroove when the sealing plate is installed to the fuel cell;(7) A sealing plate of a fuel cell according to item (3) above, whereinthe sealing plate is made from synthetic resin.

Using the methods and apparatuses discussed above, certain embodimentsof the present invention may have the following technical advantages.

According to the method for taking out a sealing plate of a fuel cellaccording to item (1) above, since the air layer is formed between theadjacent sealing plates, the adjacent sealing plates are not pressed bya pressure difference from outside surfaces toward the contact surfaceand do not adhere to each other due to static electricity. As a result,it may be possible to ensure separation of the sealing plates one by onefrom the stack of sealing plates.

Further, since the protrusion is formed in at an at least one surface ofthe sealing plate, in the stack of sealing plates, an air layer can beformed between adjacent sealing plates except the protrusion.

Further, since the taken-out sealing plate is sucked from opposite sidesthereof and the sucking pressures on the opposite sides in the case oftaking out two sealing plates are different from those in the case oftaking out one sealing plate, by detecting the sucking pressuredifference, conveyance of the sealing plates in the case of taking outtwo sealing plates to the next step can be stopped.

According to the method according to item (2) above, the presentinvention is further effective, because adhesion of adjacent sealingplates due to static electricity can be prevented by the air layerformed between the adjacent sealing plates by the protrusion, despitethat in the case of a synthetic resin sealing plate an adhesion of theadjacent sealing plates due to static electricity is likely to occur.

According to the sealing plate of a fuel cell according to item (3)above, since the protrusion is formed in the sealing plate, an air layerexists between adjacent sealing plates except the protrusion. As aresult, the adjacent sealing plates are not pressed from the outsidesurfaces toward the contact surface and the adjacent sealing plates donot adhere to each other due to static electricity, so that it ispossible to ensure separation of a sealing plate from the stack of thesealing plates one by one.

According to the sealing plate of a fuel cell according to item (4)above, since the position, the width and the height of the protrusion inthe sealing plate are determined such that the protrusion of the sealingplate is housed in a gas passage groove of a gas inlet/outlet passage ofthe separator, when the sealing plate is installed to the fuel cellseparator, the protrusion of the sealing plate is fit into the gaspassage groove of the gas inlet/outlet passage of the separator, so thatit is possible to determine in position the sealing plate relative tothe gas inlet/outlet passage in a direction perpendicular to the gaspassage groove (i.e., a gas flow direction at the gas inlet/outletpassage). As a result, a dimensional accuracy of clearances between thelongitudinal ends of the sealing plate and side surfaces of the gasinlet/outlet passage facing the longitudinal ends of the sealing platecan be low, so that a manufacturing cost of the sealing plate can bereduced by that dimensional low accuracy. Further, the clearancesbetween the longitudinal ends of the sealing plates and side surfaces ofthe gas inlet/outlet passage facing the longitudinal ends of the sealingplate can be used as a space for absorbing a bulging-out adhesive.

According to the sealing plate of a fuel cell according to item (5)above, since the width of the protrusion of the sealing plate is nearlyequal to the width of the gas passage groove, determination in positionof the sealing plate by the protrusion is of a high accuracy.

According to the sealing plate of a fuel cell according to item (7)above, the present invention is further effective, because adhesion ofadjacent sealing plates due to static electricity can be prevented bythe air layer formed between the adjacent sealing plates by theprotrusion, despite that in the case of a synthetic resin sealing platean adhesion of the adjacent sealing plates due to static electricity islikely to occur.

According to the sealing plate of a fuel cell according to item (6)above, since the protrusion is formed at a surface of the sealing plateopposite to a surface of the sealing plate facing a bottom surface ofthe gas passage groove when the sealing plate is installed to the fuelcell, air layers can be formed between adjacent sealing plates in thestack of the sealing plates like in the case where the protrusion isformed at a surface of the sealing plate facing a bottom surface of thegas passage groove. In the case where the protrusion is formed at asurface of the sealing plate opposite to a surface of the sealing platefacing a bottom surface of the gas passage groove, the protrusion isembedded in the adhesive located between the separators, a concave maybe formed in the separator facing the protrusion if necessary.

The invention may be embodied by numerous methods, systems, devices, andproducts, and the description and drawings provided herein are examplesof the invention. Other embodiments, which incorporate some or all ofthe steps and features, are also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings, which form a part of this disclosure:

FIG. 1 is a plan view of a sealing plate of a fuel cell according to afirst embodiment of the present invention;

FIG. 2 is a front elevational view of the sealing plate of a fuel cellaccording to the first embodiment of the present invention;

FIG. 3 is a side elevational view of the sealing plate of a fuel cellaccording to the first embodiment of the present invention;

FIG. 4 is a side elevational view of a stack of fuel cell sealing platesaccording to the first embodiment of the present invention;

FIG. 5 is a cross-sectional view of a portion of the fuel cell to whichthe fuel cell sealing plate is installed;

FIG. 6 is a plan view of the sealing plate where a plurality ofprotrusions are formed, of the fuel cell according to the firstembodiment of the present invention;

FIG. 7 is a plan view of the sealing plate according to the firstembodiment of the present invention where a plurality of protrusionshaving shapes which can be taken, other than a rectangle are shown in asingle sealing plate;

FIG. 8 is a cross-sectional view of a portion of the sealing plateaccording to the first embodiment of the present invention where aprotrusion having the shape of an arch as one of the cross-sectionalshapes of the protrusion which can be taken;

FIG. 9 is a cross-sectional view of a portion of the sealing plateaccording to the first embodiment of the present invention where aprotrusion having the shape of a triangle as one of the cross-sectionalshapes of the protrusion which can be taken;

FIG. 10 is a front elevational view of the sealing plate according tothe first embodiment of the invention in a case where the protrusion isformed at a surface opposite the surface of the sealing plate facing thegas passage groove;

FIG. 11 is a perspective view of a stack of sealing plates according toa comparison example;

FIG. 12 is a perspective view of the stack of sealing plates accordingto the first embodiment of the present invention;

FIG. 13 is a front elevational view of a sealing plate taking-outapparatus according to the comparison example;

FIG. 14 is a front elevational view of a sealing plate taking-outapparatus conducting a fuel cell sealing plate taking out methodaccording to a second embodiment of the present invention;

FIG. 15 is a front elevational view of a sealing plate taking-outapparatus conducting a fuel cell sealing plate taking out methodaccording to a third embodiment of the present invention;

FIG. 16 is a front elevational view of a two sealing plate taking-outpreventing portion of the sealing plate taking-out apparatus accordingto the third embodiment of the present invention;

FIG. 17 is a block step diagram according to a fuel cell sealing platetaking-out method according to the third embodiment of the presentinvention;

FIG. 18 is a flow chart of the fuel cell sealing plate taking-out methodaccording to the third embodiment of the present invention;

FIG. 19 is a side elevational view of a fuel cell stack to which thepresent invention is applied;

FIG. 20 is an enlarged cross-sectional view of a portion of FIG. 19; and

FIG. 21 is a front elevational view of a fuel cell of FIG. 19.

DETAILED DESCRIPTION

A method for taking out a fuel cell sealing plate (which includes a twosealing plate taking-out preventing method), and a fuel cell sealingplate directly used in conducting the method, respectively, according tocertain embodiments of the present invention will be explained withreference to FIGS. 1-21. The fuel cell sealing plate will be referred toas a sealing plate.

FIGS. 1-12 illustrate a first embodiment (a sealing plate taking-outmethod and a sealing plate-according to the first embodiment) of theinvention.

FIG. 14 illustrates a second embodiment (a sealing plate taking-outmethod and a sealing plate according to the second embodiment) of theinvention.

FIGS. 15-18 illustrate a third embodiment (a sealing plate taking-outmethod and a sealing plate according to the third embodiment) of theinvention.

FIGS. 19-21 illustrate a fuel cell structure applicable to anyembodiment of the present invention.

Structures common to all embodiments of the present invention aredenoted with the same references throughout all embodiments of thepresent invention.

First, structures common to all embodiments of the present inventionwill be explained with reference to FIGS. 19-21.

A fuel cell to which the present invention is applied is a solid polymerelectrolyte membrane-type fuel cell 10. The fuel cell 10 is installed toa fuel cell vehicle. The fuel cell 10 may be used for other than avehicle.

As illustrated in FIGS. 19-21, the solid polymer electrolytemembrane-type fuel cell 10 includes a layered structure of amembrane-electrode assembly 19 (MEA) and a separator 18.

The membrane-electrode assembly 19 includes an electrolyte membrane 11made from an ion-exchange membrane, a first electrode (i.e., anode) 14made from a catalyst layer disposed on one side of the electrolytemembrane 11 and a second electrode (i.e., cathode) 17 made from acatalyst layer. A diffusion layer 13 is disposed between themembrane-electrode assembly 19 and the separator 18 on the side of theanode. A diffusion layer 16 is disposed between the membrane-electrodeassembly 19 and the separator 18 on the side of the cathode.

The membrane-electrode assembly 19 and the separator 18 are layered toconstruct the fuel cell 10. A plurality of fuel cells are stacked toconstruct a stack of fuel cells. A terminal 20, an insulator 21 and anend plate 22 are disposed at each end of the stack of fuel cells. Theopposite end plates 22 are fixed to a fastening member (for example, atension plate 24) extending in a fuel cell stacking direction by a boltand nut 25. The stack of fuel cells are fastened in the fuel cellstacking direction to construct a fuel cell stack 23.

In the separator 18 located on the anode side of the fuel cell 10, at apower generating region 51, a fuel gas passage 27 for supplying fuel gas(i.e., usually, hydrogen) to the anode 14 is formed at the surfacefacing the MEA. In the separator 18 located on the cathode side of thefuel cell 10, at the power generating region 51, an oxidant gas passage28 for supplying oxidant gas (i.e., usually, air) to the cathode 17 isformed at the surface facing the MEA. Further, in the separator 18, acoolant passage 26 for supplying coolant (i.e., usually, water) isformed at a surface opposite the surface where the gas passages 27 and28 are formed. In the separator 18, at a non-power generating region 52,a fuel gas manifold 30, an oxidant gas manifold 31 and a coolantmanifold 29 are formed.

The fuel gas manifold 30 communicates with the fuel gas passage 27 via agas inlet/outlet passage 34, and the oxidant gas manifold 31communicates with the oxidant gas passage 28 via the gas inlet/outletpassage 34. The coolant manifold 29 communicates with the coolantpassage 26.

At the anode 14 of each fuel cell 10, electrolytic dissociation toexchange hydrogen to hydrogen ion (i.e., proton) and electron, and theelectron moves in the electrolyte membrane 11 to the cathode 17. At thecathode 17, water is produced and power is generated according to thefollowing equation from oxygen and the hydrogen ion and electron whichis generated at the anode of the adjacent fuel cell and comes to thecathode of the instant fuel cell, or is generated at the anode of thefuel cell located at a first end of the fuel cell stack and comes via anoutside circuit to the cathode of the fuel cell located at a second endof the fuel cell stack.

-   At the anode: H₂→2H⁺+2e⁻-   At the cathode: 2H⁺+2e⁻+(1/2)O₂→H₂O

Each fluids are sealed from each other and from outside. A first sealmember 32 seals between the two separators 18 sandwiching the MEA 19,and a second seal member 33 seals between adjacent fuel cells 10.

The first seal member 32 is a sealant made from an adhesive (sealingadhesive), and the second seal member 33 is a rubber seal member madefrom silicone rubber, fluorine rubber, or EPDM (ethylen-propylen-dienrubber). Both the first seal member 32 and the second seal member 33 maybe made from sealing adhesive or rubber seal material.

As illustrated in FIG. 21 and FIG. 5, one or more (usually, a pluralityof) concave gas passage grooves 35 are formed at the gas inlet/outletpassage 34. At the gas inlet/outlet passage 34, a sealing plate 36 isdisposed so as to cover the gas passage groove 35. In the separator, astep 37 having a depth equal to a thickness of the sealing plate 36 isformed for receiving end portions of the sealing plate 36 therein. Whenthe step 37 receives therein the end portion of the sealing plate 36, asurface of the separator 18 and a surface of the sealing plate 36 arelocated in the same plane. When the sealing plate 36 is disposed in thegas inlet/outlet passage 34, the gas passage groove 35 is covered withthe sealing plate 36 and constructs a tunnel-like passage.

The sealing plate 36 is rectangular and is disposed such that alongitudinal direction of the rectangle is directed in a gas passagewidth direction of the gas inlet/outlet passage 34. The gas passagegroove 35 extends in a width direction of the sealing plate 36. Sincegas flows in the gas passage groove 35, the width direction of thesealing plate 36 coincides with the gas flow direction at the gasinlet/outlet passage 34, and the longitudinal direction of the sealingplate 36 coincides with a direction perpendicular to the gas flowdirection at the gas inlet/outlet passage 34.

The sealing plate 36 comprises a flat plate (which may include a steppedflat plate). When the diffusion layers 13, 16 overlap with the sealingplate 36, the sealing plate 36 comprises a stepped flat plate having astep 38 for receiving the diffusion layers 13, 16 therein and having athickness equal to the thickness of the diffusion layers 13, 16. Thestep 38 extends in the longitudinal direction of the sealing plate 36. Asurface of the sealing plate opposite the surface of the sealing platefaces a bottom surface of the gas inlet/outlet passage 34 and is coatedwith the first seal member (e.g., adhesive) and faces a separator 18having an opposite polarity of the same fuel cell (i.e., a cathode sideseparator when the sealing plate is disposed at the anode sideseparator, and an anode side separator when the sealing plate isdisposed at the cathode side separator).

The sealing plate 36 is made from synthetic resin, but is not limited tosynthetic resin. The sealing plate 36 may be made from rubber, metal andcarbon, etc.

As illustrated in FIGS. 11-17, in order to determine a position of thesealing plate 36 and dispose the sealing plate in the gas inlet/outletpassage 34 of the fuel cell 10 using an automatic apparatus, firstly asealing plate 36 is taken out one by one from a stack 61 of sealingplates supplied, for example, by sucking the sealing plate by a suctionpad 62 of a sealing plate taking-out apparatus 60. Then, the taken-outsealing plate 36 is determined in position at a position determiningstation 65, and the sealing plate 36 determined in position is conveyedand supplied to an assembly step of the fuel cell 10 where the sealingplate is installed to the fuel cell 10.

It may be necessary to take out the sealing plate 36 from the stack 61of sealing plates one by one by sucking the sealing plate by the suctionpad 62. When the sealing plate 36 is flat, as illustrated comparatively,in examples of FIGS. 11 and 13, it is sometimes difficult to take outthe sealing plate 36 from the stack 61 of sealing plates one by one(i.e., as a result, two sealing plates are taken out). This is becausewhen sealing plates are layered, adjacent sealing plates closely contacteach other, and a pressure lower at the contact surface is likely lowerthan that at an outside surface (e.g., a vacuum) and/or a staticelectricity is generated at the contact surface, so that the adjacentsealing plates adhere to each other.

The fuel cell sealing plate taking-out method and the sealing plate 36directly used for conducting the method according to certain embodimentsof the present invention make it possible to take out the sealing plate36 from the stack 61 of sealing plates one by one.

More particularly, as illustrated in FIG. 12 and FIG. 14, a portion ofthe fuel cell sealing plate taking-out method common to each embodimentof the present invention is a method for the sealing plate 36 from thestack 61 of sealing plates one by one, wherein an air layer 63 is formedbetween adjacent sealing plates 36 and in that state the sealing plate36 is taken out one by one from the stack 61 of sealing plates. A methodfor forming the air layer 63 differs according to each embodiment. Themethod according to certain embodiments of the present invention mayinclude a method where when taking out two sealing plates is detected,the taking out of two sealing plates is omitted (FIG. 16).Comparatively, in the conventional method, as illustrated, for example,in FIG. 13, an air layer is not formed between adjacent workpieces 36′and a vacuum is generated between the adjacent workpieces 36′.

Some of the effects and technical advantages obtained in the portion ofthe fuel cell sealing plate taking-out method common to each embodimentof the present invention will be explained. Since the air layer 63 isformed between the adjacent sealing plates 36, the adjacent sealingplates 36 are not pressed from outside surfaces to the contact surfacethereof by a pressure difference. Further, the adjacent sealing plates36 do not adhere to each other due to a static electricity. As a result,it is possible to take out the sealing plate 36 from the stack 61 ofsealing plates one by one.

In the case where the sealing plate 36 is made from synthetic resin, thestatic electricity is likely to collect at the surface, so that theadjacent sealing plates 36 are apt to adhere to each other due to thestatic electricity. By forming the air layer 63 between the adjacentsealing plate 36, adhesion of the adjacent sealing plates 36 due to thestatic electricity can be suppressed, so that the prevention of adhesiondue to the air layer 63 becomes further effective.

Next, portions of the sealing plate taking-out method[[t]] and thesealing plates 36 directly used in conducting the method unique to eachembodiment of the present invention will be explained.

First Embodiment FIGS. 1-11

[Method for Taking Out the Sealing Plate 36 According to a FirstEmbodiment]

In the fuel cell sealing plate taking-out method according to the firstembodiment of the present invention, in order to form the air layer 63between adjacent sealing plates 36 of the stack 1 of sealing plates, aprotrusion 39 is formed as illustrated in FIG. 4 and FIG. 11. Theprotrusion 39 is formed at an outermost surface of an at least onesurface of each sealing plate 36. (The at least one surface may be asurface 40 of the sealing plate facing a bottom surface of the gasinlet/outlet passage 34, or a surface 41 of the sealing plate oppositethe surface 40, when the sealing plate is disposed at the gasinlet/outlet passage 34. The outermost surface is a surface of thesealing plate other than a surface of a recess receding by the step 38from the outermost surface.) The protrusion 39 is formed at a portion ofthe sealing plate in the direction perpendicular to the gas flowdirection at the sealing plate installing portion (i.e., the gasinlet/outlet passage 34) of the fuel cell such that the protrusion 39protrudes from the surface 40, 41. In FIGS. 1-10, the region of theprotrusion 39 is shown by a hatching, which is not a hatching for across section.

Some of the effects and technical advantages of the fuel cell sealingplate taking-out method according to the first embodiment of the presentinvention will be explained. Since the protrusion 39 is formed at the atleast one surface 40, 41 of each sealing plate 36, the air layer 63 canbe formed between adjacent sealing plates 36 of the stack 61 of sealingplates except a top of the sealing plate 36. Due to the air layer 63, avacuum (a pressure lower than the outermost surface) is not producedbetween the adjacent sealing plates 36, and adhesion due to a staticelectricity is suppressed, so that it is possible to take out thesealing plate one by one from the stack 61 of sealing plates.

[Sealing Plate 36 According to a First Embodiment]

As illustrated in FIGS. 1-11, the fuel cell sealing plate 36 accordingto the first embodiment of the present invention has a protrusion 39formed at a least one surface 40, 41 of the sealing plate 36. Theprotrusion 39 is formed at one portion of the at least one surface ofthe sealing plate in the direction perpendicular to the gas flowdirection (the longitudinal direction of the gas passage groove 35) atthe fuel cell sealing plate installing portion.

Preferably, the sealing plate 36 is made from synthetic resin, but maybe made from rubber or metal. Preferably, the protrusion 39 may beformed integrally with the sealing plate 36, but may be formedseparately from the sealing plate 36 and fixed to the sealing plate 36by an adhesive, etc.

A position, a number, a width (i.e., a width in the longitudinaldirection of the sealing plate 36) and a height (i.e., a height from thesurface 40, 41) of the protrusion 39 in the sealing plate 36 aredetermined such that the protrusion 39 of the sealing plate 36 is housedin the gas passage groove 35 of the gas inlet/outlet passage 34 of theseparator 18 when the sealing plate 36 is installed to the fuel cell 10.

More particularly, the width of the protrusion 39 of the sealing plate36 is substantially equal to the width of the gas passage groove 35. (Asillustrated in FIG. 5, since the protrusion fits into the groove 35, thewidth of the protrusion is slightly smaller than the width of the groove35.) Due to this, the protrusion 39 can fit in the gas passage groove35, and can be used for positional determination of the sealing plate 36in the longitudinal direction of the gas inlet/outlet passage 34.

The number of protrusion 39 is not limited to one, and a plurality ofprotrusions 39 can be provided as illustrated in FIG. 6. A shape of theprotrusion 39 in the plan view thereof may be a circle, an elongatedcircle and a polygon (e.g., a triangle).

A cross-sectional shape of the protrusion 39 in a plane perpendicular tothe surface 40, 41 may be a rectangle or a shape other than therectangle (e.g., an arc (FIG. 8)), a triangle (FIG. 9) or a trapezoid.When the cross-sectional shape of the protrusion is a rectangle or atrapezoid, the top of the protrusion 39 is a flat plane andplane-contacts the adjacent sealing plate when the sealing plates arelayered. When the cross-sectional shape of the protrusion is an arc or atriangle, the top of the protrusion 39 is a point and point-contacts theadjacent sealing plate when the sealing plates are layered.

As illustrated in FIG. 10, the protrusion 39 may be formed at thesurface 41 of the sealing plate 36 opposite to the surface 40 of thesealing plate 36 facing the bottom surface of the gas passage groove 35when the sealing plate 36 is installed to the fuel cell. In this case,the protrusion 39 is embedded in the adhesive contacting the surface 41of the sealing plate 36. At a portion of the adjacent separator 18facing the protrusion 39, a concave may be formed for preventinginterference with the protrusion 39.

Some of the effects and technical advantages of the fuel cell sealingplate 36 according to the first embodiment of the present invention willbe explained. Since the protrusion 39 is formed in the sealing plate 36,the air layer 63 is formed between the adjacent sealing plates 36 exceptthe protrusion 39. Due to the air layer 63, a vacuum (a pressure lowerthan the outermost surface) is not produced between the adjacent sealingplates 36, and adhesion due to a static electricity is suppressed, sothat it is possible to separate and take out the sealing plate 36 one byone from the stack 61 of sealing plates.

Since the position, the width and the height of the protrusion 39 in thesealing plate 36 are determined such that the protrusion 39 of thesealing plate 36 is housed in the gas passage groove 35 of the gasinlet/outlet passage 34 of the separator, when the sealing plate 36 isinstalled to the fuel cell separator 18, the protrusion 39 of thesealing plate 36 is fit into the gas passage groove 35 of the gasinlet/outlet passage 34 of the separator 18, so that it is possible todetermine in position the sealing plate 36 relative to the gasinlet/outlet passage 34 in a direction perpendicular to the gas passagegroove 35 (i.e., a gas flow direction at the gas inlet/outlet passage34). As a result, a dimensional accuracy of clearances between thelongitudinal ends of the sealing plate 36 and side surfaces of the gasinlet/outlet passage 34 facing the longitudinal ends of the sealingplate can be low as compared with a case where the sealing plate isdetermined in position by contacting the longitudinal end of the sealingplate with the side surfaces of the gas inlet/outlet passage 34 facingthe longitudinal ends of the sealing plate. As a result, a manufacturingcost of the sealing plate 36 can be reduced by that dimensional lowaccuracy. Further, the clearances 42 between the longitudinal ends ofthe sealing plate 36 and side surfaces of the gas inlet/outlet passage34 facing the longitudinal ends of the sealing plate can be used as aspace for absorbing a bulging-out adhesive 32.

Since the width of the protrusion 39 of the sealing plate 36 is nearlyequal to the width of the gas passage groove 35, determination inposition of the sealing plate by the protrusion 36 is of a highaccuracy.

When the sealing plate 36 is made from synthetic resin, staticelectricity is likely to collect at the surface of the sealing plate 36.As a result, the adjacent sealing plates 36 are likely to adhere to eachother due to the static electricity. However, in certain embodiments ofthe present invention, since the air layer 63 due to the protrusion 39is formed between the adjacent sealing plates 36, the adhesion due tothe static electricity is suppressed, and it is possible to take out thesealing plate one by one.

When the protrusion 39 is formed at the surface 41 of the sealing plate36 opposite to the surface 40 of the sealing plate 36 facing the bottomsurface of the gas passage groove 35 when the sealing plate 36 isinstalled to the fuel cell, the air layer 63 can be formed between theadjacent sealing plates 36 in the stack 61 of sealing plates, as in thecase where the protrusion 39 is formed at the surface 40 of the sealingplate 36 facing the bottom surface of the gas passage groove 35. In thecase where the protrusion 39 is formed at the surface 41 of the sealingplate 36 opposite to the surface 40 of the sealing plate 36 facing thebottom surface of the gas passage groove 35, the protrusion 39 isembedded in the adhesive contacting the surface 41 of the sealing plate36. By forming a concave for preventing interference with the protrusion39 if necessary, the sealing effect by the adhesive 32 can be almost notaffected by the protrusion 39.

Second Embodiment FIG. 12

[Sealing Plate Taking-out Method According to a Second Embodiment]

A sealing plate taking-out method according to a second embodiment ofthe present invention is a method where, as illustrated in, for example,FIG. 14, in order to form the air layer 63 between the adjacent sealingplates 36, a sealing plate 36 to be taken out is caused to be curvedwhen the sealing plate is sucked and taken out. The sealing plate 36positioned next to the sealing plate to be taken out is not curved.Contrarily, in a comparison example of FIG. 13, the workpiece 36′ is notcaused to be curved when sucked by a sucking pad 62′, and a placebetween the adjacent workpieces 36′ is at a vacuum or a near vacuum.

Some of the effects and technical advantages of the sealing platetaking-out method according to a second embodiment of the presentinvention will be explained. Since the sealing plate 36 to be taken outis caused to be curved, the air layer 63 can be formed between thesealing plate 36 to be taken out and the sealing plate positioned nextto the sealing plate to be taken out. Due to the air layer 63, theadjacent sealing plates 36 are not pressed from the outside surfacestoward the contact surface thereof, and adhesion of the adjacent sealingplates due to a static electricity is suppressed. As a result, it ispossible to separate and take out the sealing plate 36 surely one by onefrom the stack 61 of sealing plates (without taking out two sealingplates).

[Sealing Plate Taking-Out Apparatus According to a Second Embodiment]

A sealing plate taking-out apparatus 60 according to the secondembodiment of the present invention is, as illustrated in, for example,FIG. 12, an apparatus directly used in taking out the fuel cell sealingplate 36 from the stack 61 of sealing plates. The apparatus comprises asuction pad 62 for sucking a central portion of the sealing plate 36,and projections 64 located on opposite sides of the suction pad 62 inthe longitudinal direction of the sealing plate 36 and projecting towardthe sealing plate 36 more than an end of the suction pad 62.

Some of the effects and technical advantages of the sealing platetaking-out apparatus 60 according to the second embodiment of thepresent invention will be explained. Since the sealing plate taking-outapparatus 60 comprises the suction pad 62 for sucking a central portionof the sealing plate, and the projections 64 pushing the sealing plate36 at a portion other than the sucking portion of the sealing plate bythe suction pad 62, the suction pad 62 and the projections 64 can bendthe sealing plate 36 to be taken out in the form of an arch. As aresult, between the sealing plate 36 to be taken out and the sealingplate 36 positioned next to the sealing plate to be taken out, the airlayer 63 a thickness of which becomes largest at the central portion ofthe longitudinal direction of the sealing plate 36 can be formed. Due tothe air layer 63, it is possible to ensure separation and take out thesealing plate 36 one by one from the stack 61 of sealing plates (withouttaking out two sealing plates).

Third Embodiment FIGS. 15-18

[Sealing Plate Taking-Out Method According to a Third Embodiment,Including Stopping Supply in the Case of Taking Out Two Sealing Plates]

In the fuel cell sealing plate taking-out method according to the thirdembodiment of the present invention, after taking out the sealing plate36 and before installing the taken-out sealing plate to a fuel cell, thetaken-out sealing plate 36 is sucked from opposite surfaces thereof Whentaking out of two sealing plates is detected, conveyance of the sealingplates 36 to the assembly step of the fuel cells is stopped.

In more detail, as illustrated in FIGS. 15-17, after taking out thesealing plate 36 and before installing the taken-out sealing plate to afuel cell, at a sealing plate position determining station 65 (whereusing a position determining plate 66, a position of the sealing plate36 is determined in the longitudinal direction and/or the widthdirection of the sealing plate 36), the sealing plate 36 taken out fromthe stack 61 of sealing plates and conveyed to the sealing plateposition determining station 65 is sucked from the opposite sidesthereof (e.g., from an upper side and a lower side of the sealing plate,or from horizontally opposite sides of the sealing plate), using asuction pad 62 and a suction plate 67. The suction by the suction pad 62and/or the suction plate 67 is different between the case of taking outone sealing plate and the case of taking out two sealing plates. Whentaking out two sealing plates is detected using the suction difference,conveyance of the sealing plates 36 to the assembly step 80 of the fuelcell is stopped. Usually, the suction force of the suction plate 67 isincreased, and when the suction of the suction pad 62 operates to ON,taking out of two sealing plates is deemed to happen, and the conveyanceand supply of the sealing plates 36 to the next step (the assembly step80 of the fuel cell) is stopped. In FIGS. 15 and 16, arrow S showssuction. Further, in FIG. 16, arrow R shows raise of the suction pad 62.

FIG. 18 shows one example of a flow of steps of fuel cell sealing platetaking-out method including a step for preventing taking out of twosealing plates.

In FIG. 18, at step 101, a routine for taking out one sealing plate 36from the stack 61 of sealing plates is begun. Taking out one sealingplate only is conducted by proceeding to step 102 where the protrusion39 formed at the sealing plate 36 is used, or proceeding to step 103where the sealing plate 36 is bent in the form of an arch. Any one ofsteps 102 and 103 may be adopted. Then, the routine proceeds to step 104for preventing taking out of two sealing plates. At step 105, a sealingplate 36 is placed on the suction plate 67 if the position determiningstation 65. Proceeding to step 106, both suction of the suction pad 62which is a taking-out tool and suction of the suction plate 67 are madeON. Proceeding to step 107, the suction pad 62 which is a taking-outtool is raised. Proceeding to step 108, a suction pressure of thesuction pad 62 which is a taking-out tool is examined so that whether asucked workpiece (a second workpiece in the case of taking out twosealing plates) exists or not is confirmed. When a workpiece sucked bythe suction pad 62 exists, the suction pressure of the suction pad 62 isgreater than the atmospheric pressure, while when a workpiece sucked bythe suction pad 62 edoes not exist, the suction pressure of the suctionpad 62 is zero (the atmospheric pressure).

When a workpiece sucked does not exist, proceeding from step 108 to step109, after confirming at step 109 that a workpiece sucked does notexist, at step 110 the suction pad 62 conducts the next operation (wherethe suction plate 67 makes its suction OFF and the suction pad 62conveys and supplies the sealing plate to the assembly step 80 of thefuel cell). At step 111 the routine is completed and returns to step 101where the next taking-out of the next workpiece begins.

When a workpiece sucked exists, proceeding from step 108 to step 112,after confirming at step 112 that a workpiece sucked (a second sealingplate) exists, at step 113 generation of NG is confirmed. Then, at step114, ejecting out the second sealing plate 36 (corresponding to step 68of FIG. 17) is conducted, and then the routine returns to step 101 wherethe next taking-out of the next workpiece begins.

According to the fuel cell sealing plate taking-out method according tothe third embodiment of the present invention, since the taken-outsealing plate 36 is sucked from opposite sides thereof, taking out twosealing plates can be detected by detecting the suction pressures usingthe routine of FIG. 18, because the suction pressures on the oppositesides differ from each other between in the case where two sealingplates are taken out and in the case where one sealing plate is takenout. When taking out of two sealing plates is detected, conveyance andsupply of the sealing plates taken out to the next step can be stopped.As a result, incorrect installing of the sealing plate 36 can beprevented.

[Sealing Plate Taking-Out Apparatus According to a Third Embodiment]

A fuel cell sealing plate taking-out apparatus 60 according to a thirdembodiment of the present invention directly used in conducting thesealing plate taking-out method includes an apparatus for preventingtaking out two fuel cell sealing plates disposed at a portion of asealing plate conveyance route after taking out a sealing plate 36 fromthe stack 61 of sealing plates and before installing the taken-outsealing plate to a fuel cell. The two sealing plate taking-outpreventing apparatus includes the suction plate 67 and the suction pad62 which suck the sealing plate taken-out from the stack 61 of sealingplates from opposite sides thereof (for example, from an upper side anda lower side of the sealing plate).

According to the fuel cell sealing plate taking-out apparatus 60according to the third embodiment of the present invention, since theapparatus includes the suction plate 67 and the suction pad 62, takingout two sealing plates can be detected by sucking the taken-out sealingplates from the opposite sides thereof (e.g., from the upper side andthe lower side of the taken-out sealing plates), and conveyance andsupply of the taken-out two sealing plates to the next step (fuel cellassembly step 80) can be stopped.

The examples described herein are merely illustrative, as numerous otherembodiments may be implemented without departing from the spirit andscope of the exemplary embodiments of the present invention. Moreover,while certain features of the invention may be shown on only certainembodiments or configurations, these features may be exchanged, added,and removed from and between the various embodiments or configurationswhile remaining within the scope of the invention. Likewise, methodsdescribed and disclosed may also be performed in various sequences, withsome or all of the disclosed steps being performed in a different orderthan described while still remaining within the spirit and scope of thepresent invention.

The invention claimed is:
 1. A method of taking out a sealing plate of afuel cell from a stack of sealing plates, the sealing plate being to beinstalled to a gas inlet/outlet passage of a fuel cell so as to cover agas passage groove formed at the gas inlet/outlet passage, said methodcomprising: a first step of taking out the sealing plate one by one fromthe stack of sealing plates under a state that an air layer existsbetween adjacent sealing plates of the stack of sealing plates; and asecond step, provided between the first step and a step of installingthe taken-out sealing plate to the fuel cell, of (a) placing thetaken-out sealing plate on a suction plate, sucking the sealing platefrom opposite sides of the sealing plate by the suction plate and asuction pad thereby detecting taking out of two sealing plates based ona suction difference between a case of taking out a single sealing plateand a case of taking out two sealing plates, and (b) stopping conveyanceof the sealing plate to the step of installing the taken-out sealingplate to the fuel cell when taking-out of two sealing plates isdetected, wherein in order to obtain the state that an air layer existsbetween adjacent sealing plates of the stack of sealing plates at thefirst step, a protrusion is beforehand formed so as to protrude in athickness direction of each sealing plate at an at least one surface ofthe sealing plate and at a portion of the sealing plate whichcorresponds to a portion of a sealing plate installing place of the fuelcell in a direction perpendicular to a gas flow direction at the sealingplate installing place.
 2. A method according to claim 1, wherein thesealing plate is made from synthetic resin.